Ranney was born in Middletown, Connecticut. As a young man, he began studying art in New York City.  After the death of his father, a captain in the West Indies trade, Ranney moved to Fayetteville, North Carolina. He became an apprentice to a tinsmith and began exploring the South. In 1836 he joined Texas army in its fight for independence against Mexico, and during this period, he became deeply influenced by the frontier. For the rest of his life, he would paint scenes of the West. 

Following his time in the army and experience on the western frontier, he returned to New Jersey were he and his family settled. In 1853 he built a large studio and committed his artistic career to depicting images of hunters, trappers, and prairie families.

Ranney his best known for his paintings of pioneers, trappers, and scouts, and portraits of important Western figures such as Daniel Boone. He created romantic scenes of the Revolutionary War and did numerous hunting scenes, using from the New Jersey marshes as a setting.  Although not trained in Europe, his style consisting of soft, refined brushstrokes and a dark, atmospheric palette are highly reminiscent of British hunting scenes. Ranney became best known for his large-scale hunting scenes, which are his most desirable subject for collectors of his work.

William Ranney has produced a large body of work and is acknowledged by the fine art community as a significant professional artist. Ranney’s work has been exhibited throughout the world and his painting are in the collections of the Boston Fine Arts Museum, Corcoran Gallery of Art, Dallas Museum of Art, The White House, Thyssen-Bonemisza Collection, among others.